During the past several decades, surgical techniques have sought to become more conservative in the amount of tissue that is excised for various diseases. Nowhere is this more apparent than in the realm of breast surgery for neoplastic disease, wherein, as surgical techniques have developed, there has been greater refinement in the use of breast-conserving surgical therapy—often termed “lumpectomy.” As such, the goal of the lumpectomy procedure is to remove all cancer from a particular site, sparing as much of the “normal” breast tissue as possible and thus optimizing the final cosmetic appearance of the involved breast while removing all cancer.
One accepted guideline for the excisional breast biopsy (i.e., lumpectomy) is to obtain an entire peripheral layer of non-neoplastic tissue around the cancer. In cases in which the neoplastic tissue is in the form of a tumor, the success of the surgical lumpectomy is based on the completeness of removal of the tumor plus a rim of normal tissue equal to or greater than a prescribed margin (for example 3 mm) along the entire periphery of the tumor. Thus, whenever a surgeon performs an excisional biopsy (i.e., removes a cancerous tumor), care must be taken to ensure that an adequate margin of non-cancerous tissue surrounding the cancerous tumor is also removed. The removed tissue, including the tumor and surrounding non-cancerous tissue, may be referred to generally as a specimen, or more specifically as a biopsy specimen or, in cases in which the removed tissue is breast tissue, a lumpectomy specimen.
After removal, the surgeon provides the biopsy specimen to a pathologist, who closely examines and dissects the specimen to ensure, inter alia, that an adequate surrounding non-cancerous tissue margin was maintained around the cancerous tumor. If an adequate margin was not maintained, the pathologist attempts to direct the surgeon to precisely where the margins were not maintained so that additional tissue can be excised to ensure that margins are ultimately maintained. Unfortunately, it is often difficult to properly communicate precisely where the margins were not maintained, and, hence, exactly from where additional tissue needs to be excised. The difficulty of ensuring that sufficient margins are maintained is further complicated by the fact that cancerous tumors often grow in non-uniform and irregular shapes.
Current practice to determine the adequacy of margins involves the pathologist dissecting the specimen into multiple slices, processing the slices into glass slides which can be viewed with a microscope, and examining the boundaries of each slice or slide to identify and measure the boundaries of the neoplastic tissue (e.g., cancerous tumor) and the margin of the surrounding non-cancerous tissue. Unfortunately, this process only realizes the boundaries of the cancerous tumor and the margins in two dimensions, and thus, does not account for the orientation of the examined boundaries with respect to the original removal site, or the rest of the excised tissue. Therefore, if inadequate margins are found, it is often difficult to precisely communicate back with the surgeon (or other treating physician) exactly from where (in relation to the removal site of the patient) additional tissue needs to be excised so that tissue removal is optimized while maintaining adequate safety margins. This normally results in non-optimal (and unnecessarily excessive) removal of non-cancerous tissue from the patient.